High-frequency signaling system



July 17, 1928. 1,677,268

W. J. BROWN HIGH FREQUENCY SIGNALING SYSTEM Filed June 2, 1924 f7 .5 44 j .45 I n kmam/e 4/ )1 Ccm/b/ner WITNESSES: INVENTOR 4 V lA a/fien/obn Brow/1.

' I I ATTORNEY Patented duly 17, 1928..

wnn'rnn Jenn snow, or nvnnsLnY, nnemnn, assrenon, BY nasnn assxennnnaa,

romnrnoromran-vrcnnns nLncrnIcaL company, Lmrrnn, a nnrrrsn ronaujsrocn conranr.

men-rnneunrvor SIGNALING sr's'rnia.

Application filed June 2, 1924, Serial No. 717,248, and in Great nmain time a, was.

. My invention relates to radio signaling systems and more particularly to systems having means for rendering them operative with a wide rangerof frequencies.

One object of my invention 18 to provide a radio receiving set which shall be selzicontained and which shall receive effic ently,

over a lengths g I D Another object of my invention is to produce a radioreceiving device having conveniently interchangeable inductances and teedback means-whereby a change of sensitivity from one group of frequencies to another group of frequencies is made by means which provide maximum convenience of operation.

Another object of my invention 15 to provide a receiving system having feed-back means which shall hev difficult to set nto oscillation even when operated by unskilled persons.

Another object of my 1nvent1on 1s to produce a radio receiving system havlng a glurality of groups .of interchangeable in netances adapting the deviceto be operated at different wave lengths.

Another object of my inventionis-to produce a radio receiving apparatus having a plurality of interchangeable grou s 0:. 1nductances and feed-back:means a apted to be interchanged conveniently and to make connection automatically to othenportions of the apparatus to be contained In a subcontainer and adapted to be mounted with thermionic discharge devices in a ma n container. v 1

- In the prior art of the reception of radio signals by means of regenerative receptors,

it is well known that when the regenerative feed-back coupling is increased to a-certain value, depending on several conditions of the,"

. apparatus, undesirable continuous oscillaradiations from the aerial.

tions will be set up which may result in Thus when the regenerative coupling is efi'ected by means of an inductance coil which is in, or related to, the output circuit of a triode electron dischargevalve and which is magnetically coupled with an inductance coil ,of an input circuit of the said. valve-or a preceding valve, the conditions for self-oscillation are determined by the mutual inductance between the coils of the output and input circuits. They are also determined by the plurality of desired bands of wave ratio of the self induction and capacity in the circuits, the ohniicresistance and especially by the self-induction of the reaction coil when the-back cou ling is controlled byvariation of the physical position of the reaction coil with respect to an input coil.

Thus ina complete and self-containedre- I ceiving set the coils between which the back coupling is efl'ected may be made of sucha size that when the circuits are otherwise suitablyadjusted, undesirable self-oscillationscannot be setup, while, at the same time, reception at relatively high eficiency is obtainable. These edects are only possrble, however, over a relatively small band of wave lengths since under these conditions,

the self-induction of the reaction coil necestance for a relatively long wave length is used along with an input inductance for receiving shorter wavelengths, undesirable self oscillation may be' readily set up and mag even be dificult to stop. '1

ccording to one feature of the present invention the inductances, such as. a tuning inductance in the input circuit of a valve and a tuned anode coil, or a reaction coil are disposed in a compartment, framework or casing which s separate from, and re ill movable with respect to, the main casing containing the valve and other apparatus, such, as condensers, filament rheostats, va- I'lOllS external terminals and other devices.

The connections between the removable comartment and the main casin may be et-' iected by means of contacts which are adapted to engage corresponding contacts provided on the main casing and at 'thesame time preferably rendered inaccessible when the said removable compartment is placed in its operative position. The coils contained in the removable compartment are sealing t e compartment. A pluralitybf such removable compartments may be protee vided, each one containing a diderent set of v coils, permitting reception over bands of progressively increasing wave lengths.

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ing description when read in connection with the accompanying drawing wherein:

Figure 1 is a diagrammatic representationof circuits and apparatus embodying my invention.

Figure 2 is a perspective view of a conventional receivin set cabinet modified according to a prefhrred form of my invention.

in the drawing, the valves are indicated at 1, 2, 3 and l. The valves 1, 2 and 3 are highfrequency am lifiers and the valve t is a detector. The ilaments of several valves are supplied with current from a -suitable source (not shown) thepositive pole of which is connected to the conductor 5 and the negative pole to the conductor 6. The filament current ma be regulated in any desired manner. or example, a rheostat (not shown) may be arranged in one of the filament leads of each of the valves.

The aerial tuning inductance is indicated V at 7 and may be variable. Une terminal 8 of theinductance 7 is connected'to the aerial 9 through a series tuning condenser 10. It will be understood that the tunin condenser may be connected in arallel with the inductance 7 or the in uctance 7 may be a variometer used with or without a tuning inductance 7 is. connected to earth as indicated at 12, through a conductor 13 and an earthed bus-bar 14 which will be hereinafter again referred to.

The terminal 8 of the inductance 7 is connected to the grid of the first valve 1 as shown, and the anode of the valve is con nected to a high tension battery through an inductance 15 and positive terminal 18.

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The negative pole of the high tension bat-' tery is connected to the conductor 5 as will be well understood. The inductancelb constitutes the primary winding of a loosecoupled high-frequency transformer 17, the secondary winding 18 of which is connected, at one end to the grid of the second valve 2 and at the other end to the earthed bus-bar it. i o

, The primary winding 15 of the transformer 17 is adapted to be tuned by means of a variable condenser 19 which is connected between the. anode of the first valve The other terminal ll of the terrace and the earthed bus-bar it. The secondary winding 18 of .the high frequency tI'iLIlSr former is adapted to be similarly tuned by means of a variable condenser 20 connected between the grid of the second valve and the buss-bar 14.

lit will be'understood that the coupling. between the first and second valves may assume other forms. For example, the cow plin between the primary and secondary windings of the transformer 17 may be close andfixed and only one of the windings tuned by means of a condenser. The invention also includes the use of an inductancecapacity' coupling between the first and sec ond' valves-in place of a high-frequency transformer, but. the loose-coupled transformer is to be preferredwhen selectivity is re uired.

The'third valve 3 is coupled to the second valve 2 by means of a small condenser 21 connected between the anode of the second valve and the grid of the third valve, a grid leak 22 being connected between the grid of the third valve and the negative filament conductor 6.

The second valve is provided with an anode inductance 23 which is connected to all the high-tension positive terminal 1e and which is tuned bymeans of a variable condenser 24:, connected between the anode of the second valve and the bus-bar 14. The third valve is provided with an anode coil 25 which is connected through a reaction coil 26 to the high tension positive terminal 16. The anode circuit of the third valve is tuned by means of a variable condenser 27 which is connected between the anode of the third valve and the bus-bar 14. The reaction coil 26 is variably coupled with the secondary winding 18 of the high frequency transformer 17.

llf desired, the reaction between the third and second valves may be floating, that'is to say, it may comprise a coil such as 26 having a fixed coupling with the winding 18 of the transformer and a second coil in parallel therewith variably coupled with the anode coil 25 of the third valve. Alternatively,

the coil 26 may have a variable coupling with the winding 18 of the transformer, while the second coil has a fixed coupling with the anode coil 25. Or, if desired, both the couplings may be variable. The floating! circuit containing two such reaction coils may be connected to a part of the circuit which is normally at a fixed potential, for example, the bus-b r 14;.

The anode of the t ird valve 3 is connected to the grid of the fourth valve lby Witt low

dicated at 30 a) the high-tension positive ter-' minal 16. The usual telephone and high tension battery bridging condensers 31 may be provided asshown.

The potential of the 'earthed' bus-bar 14 with respect to the filament is adjusted by means of a potentiometer 32 which'may be connected across the positive and negative filament leads and {5. The potentiometer 32, which may be fixedor variable, determines the potential of the grids of the valve 1 and 2 with, respect to'the. filaments of these valves. 7 All the tuning coils including the windings of the transformer 17 and the reaction coil 26 are disposed in a-compartment or casing which is indicated at 33 by dotted lines. Such compartment or casing is separate from, and removable with respect. to, the

main casin (not indicated) containing all the other evices of the receiver, including the aerial tuning condenser '10, the intervalve tuning condensers 19, 20, 24 and27 "and the external terminals. The connections between the removable compartment 33 and the main casing are preferably effected by means of pairs of contacts 34 so arranged as severally toengage one another when the *compartment 33 isproperly located with respect to the main, casing. As previously .set forth, the pairs'of contacts 34 may be so,

located that they are inaccessible when the l compartment 33 is in its operative position.

front of which is aflixed a I 15, 18, 26, 23 and 25. Means for'adjusting the "coupling between the several inductance devices, 15,18 and 26, and int varying the operative position of the inductance device 7 are preferably carried by the compartment- 44 and should be so arranged-as to beaccessible from the exterior thereof. 2 These control devices are not illustrated, inasmuch as the manner in which they would be mounted-is believed to be sufliciently obvious.

The cooperating contacts carried by' tlie' removable container and by the'main casing are also not illustrated, inasmuchas their specific 'arrangement'would be a "matter well within the capacity of anyone skilled in. the art. The; manner in which the said contacts cooperate is clearly shown in Fig. 1.

The invention is. not limited, however, to

the use of pairs oi contacts 34; smce ordinary terminals may be employed adapted to be connected by wire. The coils in the compartment 33 are suitable for reception over a definlte band of wave lengths. A lurality of movable compartments 33 may prohaving.

inductances in said said electron devices in said othercontarilerivided, each containing a different set of coils suitable for reception over different bands of wave lengths. :In this manner, the possibility of setting up strong self-oscillation which is liable to be radiated from the aerial and cause disturbance is minimized on may even be prevented if the compartment 33 is sealed and the contacts 34 are rendered inaccessible as above mentioned.

The main casing is conveniently provided with an open compartment adapted to receive the compartment 33.

While I have shown but a single embodiment of my invention in the accompanying drawing, it is capable of various changes and modifications .without departing from the spirit thereof and it is desired, therefore,

that only such limitations shalt be imposed thereon as are indicated in the prior art or in the appended claims.

I claim as my invention: A 1. A radio receiving system comprising in combination a-radio receptor circuit com-- g'rising an inductance, a triode amplifier evice comprising electron discharge means and grid and plate inductances'electroma netically coupled and associated with said receptor circuit, additional amplifier means comprising electron discharge means and inductances, a detector, a container, a removable sub-container therewithin, said in-- 'ductances being positioned therein, and re-',

movable therewith, and means whereby the inductances positioned in said sub-container are connected in circuit when the sub-container is inserted into said container.-

2. A' radio receiving system comprising in combination a radio receptor circuit com prising an 1nductance,- a triode amplifier device comprising electron discharge means 'and grid and late inductances electromag' netically coup ed and associated with said receptor. circuit, additional amplifier means 'COmPIISIIlg electron discharge means and.

inductances, connectionsbetween said electron devices and said inductances, a detector,

a container and a removable sub-container therewithin, said inductancejs being positioned therein and removable therewith, said connections separably extending between sub-container and 35,51 radio receiving system comprising in combination' a'radio receptor, an electron discharge device having a grid coil, and a feed-back coil inductively coupled "thereto,

a container, a removable sub-container...,1 .si.

therein having said coils positioned therewithin, and'means whereby "the coils positioned in-saidsub-container are connected in circuit when the sub-contalner'i's inserted.

into said container.

4. A radio receiving system comprising 'in combination a radio receptor circuit having an inductance device therein, an amplitier apparatus comprising electron discharge means, an input'inductance, an output inductance and-a feed-back inductance, a detector, capacitive tuning means associated .With said inductances, a removable sub-containe'r, said inductances being positioned therein, a mam container, and means for COIlYlQ-Ztli'lg said inductances to said discharge means by the operation of placing said subill container Within said main container.

5. A radio receiving system comprising in combination .a radio receptor circuit having an inductance device therein, an amplifier apparatus comprising electron discharge means, an inputinductance, an output inductance and a feed-back inductance, a detector, capacitive tuning means associated With said inductances, a removable sub-con tainer, said inductances being positioned therein, a main container, and means t'or connecting said inductances to sai'dgdisch'arge means by the operation of placing said subrontainer .within said mam container, and a plurality of other sub-containers andother inductances therein, interchangeable With said first-mentioned subrcontainer and theres With'inductances.

6. A radio receiving system coin rising in combination a radio receptor circuit hare, 111g an nductance'devlce therein, an amph fier apparatus comprising electron discharge means, an mput Inductance and a feed-back inductance, a detector, capacltlve tuning i terrace means associated with said indnctances, a removable sub-container, said inductances being positioned therein, a maincontainer and means for connecting said inductances to said discharge means by the operation of placing said sub-container Within said main container, and a plurality of other subcontainers and other inductances therein,

interchangeable with said firstmentioned maining inductors, contact devices carried enternally by said container, additional radio receiving apparatus including thermionic devices and variable reactors, and contact devices connected to said thermionic devices and variable reactors and arranged to cooperate with the contact 'devicescarried by said container, the said reaction coil having insufiicient inductance to cause 0s-. "cillatlon at any position of its varlable coupling range.

ltn testimony whereot, l[ have hereunto" subscribed my name this 9th day of May, 1924. I

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